The transmission of ultrasonic waves in intact and discontinuous strong rock has been investigated. The purpose of the work was to provide information on the wave velocity ratio approach of determining rock quality that has been proposed by others working in this field. Tests were carried out to investigate the effects of normal stress on the compressional wave velocity across a closed discontinuity, and also to determine wave velocity, attenuation coefficients and the effect of uniaxial compressive stress in intact samples of rock. The results showed that although ultrasonic techniques are useful for studying the dynamic properties of materials in the laboratory, the wave velocity ratio method of assessing rock quality in the field could be limited by the nature of the surface of the discontinuities, and by the stress across them. (Author/publisher)
Abstract